PurposeAs more treatments emerge for advanced, stage IV non-small-cell lung cancer (NSCLC), oncologists have difficulty predicting functional resiliency versus functional decline throughout cancer treatment. Our study evaluates functional resilience among patients with advanced NSCLC. MethodsFunctional status was evaluated through 12 months of follow-up based on disability score using the modified EQ-5D-5L (mEQ-5D-5L) survey. Participants were classified into 4 groups: functional maintenance, decline, resilient, or variable. Characteristics of 207 participants with newly diagnosed NSCLC included demographics, comorbidities, baseline Eastern Cooperative Oncology Group (ECOG) performance status (PS), mEQ-5D-5L scores, psychological symptoms, and lung cancer-specific symptoms. Treatment toxicity and grade were recorded. Resilience was defined as improvement from baseline disability scores. A 1-point increase in functional status score represents a 0.5 standard deviation change on the mEQ-5D-5L. Differences between the 4 groups were determined through Fisher’s exact test or ANOVA. Kaplan-Meier curves describe overall survival (baseline through 18 months) stratified by baseline mEQ-5D-5L scores. ResultsAmong participants, 42.0 % maintained functional status, 37.7 % experienced functional decline, 10.6 % were resilient, and 9.7 % had variable functional status. Participants with the best baseline function (score of 0) had the longest overall survival and participants with the worst baseline function (score of 5 + ) had the shortest overall survival. Among the healthiest patients, early score increases indicated shorter overall survival. Baseline ECOG PS was not associated with overall survival (p = 0.47). ConclusionBaseline functional status may help better predict functional resiliency and overall survival than ECOG PS among patients receiving treatment for advanced NSCLC.